HOMA, QUICKI and MFfm to measure insulin resistance in morbid obesity.

Background: The relationship between morbid obesity (MO) and insulin resistance (IR) has been widely demonstrated. The euglycemic-hyperglycemic clamp method for diagnosis of IR is neither practical nor cost-effective for population-based studies. However, the application of mathematical models (HOMA, QUICKI and Mf(fm) indices) can be useful.

Methods: The data from 171 patients were retrospectively evaluated. We recorded general anthropometric parameters and the basal levels of glucose, triglycerides and insulin and calculated the metabolic indexes both before surgery (Capella gastric bypass) and 6, 12, 24, 36 and 48 months after the operation.

Results: Before surgery, patients could be classified according to their waist-hip ratio (WHR) into 2 groups. Group A (n = 131, 108 females and 23 males) with WHR values 1.10 +/- 0.1 SD for males and 0.94 +/- 0.1 for females (central obesity); and Group B (n = 40, 34 females and 6 males) with WHR values 0.90 +/- 0.1 for males and 0.84 +/- 0.1 for females (peripheral obesity). Group A patients showed elevated serum levels of glucose, triglycerides and insulin and high values of the HOMA index with low values of QUICKI and Mf(fm). Group B patients showed lower levels of glucose, triglycerides, insulin and HOMA index and higher values of QUICKI and Mf(fm). These abnormal levels began to decrease 6 months after bypass and the QUICKI and Mf(fm) began to increase.

Conclusions: The high baseline levels of insulin and the high prevalence of hypertension, diabetes or both conditions in patients with central obesity confirm that they suffer a metabolic syndrome, Meanwhile, patients with peripheral obesity with lower levels of chemical parameters and of the metabolic indices suffer peripheral resistance against insulin. Clinical application of these mathematical indices can be useful in patients with MO; they are easily performed and lack the high costs and risks associated with the clamp technique.